Screw-cutting die



(No Model.)

T. L. SMITH. SGREW GU'ITING DIE.

No. 421,773. Patented Feb. 18, 1890.

UNITED STATES PATENT FFICE.

THOMAS L. SMITH, OF MILWVAUKEE, VVISCONSIN, ASSIGNOR TO THE PRATT & IVHITNEY COMPANY, OF l-IARTFORD, CONNECTICUT.

SCREW-CUTTING DIE.

SPECIFICATION formng part of Letters Patent No. 420,773, dated February 18, 1890.

Original applieaton filedAugust 30, 1887, Serial Na. 248,240.

Divided and this application filed February 23, 1889. Se1ial No. 300,917 (No model.)

T all whom it may concern:

Be it known that I, THOMAS L. SMITH, a oitizen of the nted States, residing at Milwaukee, in the county of Milwaukee and State of IVisconsin, have invented certain newand useful Improvements in Screw-Outting Dies, of which the following is a specifioation.

This application is a division of my application, Serial No. 248,240,fi1ed August 30, 1887.

This invention relates to that class of screwcutting dies having adjustable and renewable chasers, and has for its object to furnish an improved die of that class in whioh the chasers are removably held in place by means independent of and located within the adj 11sting-ring, whereby said chasers may be removed and replaced without disturbing the adjustment of said ring.

In the draWings aocompanying and forming a part of this specification, Figure 1 is a plan view of a sorew-cutting die embodying 1ny improvements. Fig. 2 is an opposite plan view of the same. Fig. 3 is a side elevation drawn in projection Wit-h Fig. 1. Fig. 4 is a seotional elevation in about line a a, Fig. 1. Fig. 5 is a section in line 5 b, Fig. 1. Fig. 6 shows ons form of the chaser-clamping srew.

Similar characters designate like parts in all the figures.

The body of the die or the collet which oarries the series of chasers is designated by A, and is bored, substantially as shown, to permit the passage through it of the bolt to be threaded. The chasers B are carried in a series of slots b, substantially radially disposed in the front part or annulus of said collet A, and are provided each With thread-outting teeth 5 of the usual description. The outer ends 4 of the ohasers are formed inclined to furnish a proper hearing for the adj ustingring O, which is screwed onto the annulus N, and is beveled t0 bear on said ends. Screwin g the said ring farther onto the collet serves to force the ohasers inwardly, while to turn 45 the ring oppositely perinits the chasers to be forced outwardly loy the piece loein g threaded, 01 by other means. The ring 0 should be fitted to turn closely on the thread 3 of said part N, 01 be provided with well known meansas, for instanoe, the clamp-screw 6- for temporarily fixing the same firmly on the collet or annulus.

For holding the ohasers in place in the chaser-receivin g slots b, I provide a removable clamp device S, which is accessilole from the face or front of the die and interseots the slots b, as shown. This device is made in two forms, the simpler form being shown in Fig. 6, where one screw is used for eaoh chaser. The other form in Figs. 1, 3, 4, and 5 is a ring hearing on all the ohasers. For the purpose of receiv ing this ring, the part N is extended beyond the chasers, as shown, and has on the inner side thereof a thread, into which the clamp ring or screw S is closely fitted. The lower edge 7, Fgs. 4 and 5, of the ring S bears on the several chasers, and thus clamps then1 down firmly to the bottom of slots b. The lower side or face 8 of the die in Figs. 3, 4, and 5 is considered the front of the sa1ne, and accordingly I set the chasers inclined, as shown, so as to bring the teeth 5 near to s a1d face 8, whereby the die is adapted for cutt1ng a thread up olosely to the head of the bolt. Pockets or cleaiance spaces 9 are usually made in the ring S, 01 in the body A, er 111 both, to facilitate the escape of chips.

By means of the clamp-ring 0 and by loosenii1g the screws S the chasers may be taken out, reground, and replaeed without d1sturbing their adjustment. Where large numloers of pieces are to be uniformly'threaded, th1s feature beoomes very important, and 1t 1s for this class of work that the present improvement is espeoially designed and used.

The die may be used by inserting the collet A Within the circleof a diestock in the usual manner, or it may be provided With handles 12 (not fully shown) for that purpose.

The operation of cutting a thread is carned go out in the usual 1nanner, the chasers being first set to the required position radially of the collet by the n1eans descrioed, orby other well-known n1eans therefor, not shown here in, hut shown in prior Letters Patent.

Having thus described rny invention, I claim- 1. In a sorew-outting die, the combination, With the oollet internally threaded' and having radially-disposed ohaser-receiving slot-s, of 1 00 

